British Columbia Combustible Dust Hazards Awareness Workshops

Workplace combustible dust related fires and explosions occur with alarming regularity in the global grain, mining, forestry and manufacturing sectors. Although the majority of incidents do not result in fatalities, injuries, or property damage, historically many of these non-consequential incidents have been precursors to catastrophic events.

The complex topic of combustible dust hazards recently came to the forefront in British Columbia when WorkSafeBC issued a directive order for all sawmills to conduct a comprehensive risk assessment resulting in an effective dust control program. 

In conjunction with FireWise Consulting Ltd., John Astad, Director and Research Analyst from the Combustible Dust Policy Institute (CDPI) will be presenting a series of one day Combustible Dust Hazards Awareness Workshops throughout British Columbia. The goal of the CDPI is to minimize the severity and reduce the occurrence of combustible dust related fires and explosions through research of combustible dust related incidents. For more information on the CDPI  view brochure here.

The Combustible Dust Hazards Awareness Workshop will provide stakeholders with the knowledge to minimize the probability of occurrence and severity of consequence of future combustible dust related incidents. In addition the workshop will assist stakeholders in developing a comprehensive dust control program as noted in the revised WorkSafeBC OHS Guidelines. Key aspects of the workshop are identifying, evaluating, and controlling combustible dust hazards in addition to providing guidance in conducting facility inspections and risk assessments.

Facility owners and managers concerns in reducing the probability of a catastrophic secondary dust explosion include good housekeeping, employee training, maintenance, and management of ignition sources. Prevention of future incidents begins with awareness of the problem and a robust hazard mitigation framework which consists of a facility risk assessment, written combustible dust program, and hazard communication.

This combustible dust workshop will discuss the importance of these topics and more in addition to the BC Fire Code referencing the National Fire Protection Association (NFPA) combustible dust standards. NFPA best industry practices include engineering controls for deflagration suppression, deflagration isolation, and explosion venting in the mitigation of combustible dust explosions. The NFPA 664 Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities provides excellent guidance in this area and is a key resource for the workshop.  Click here for a detailed course outline.

COURSE DETAILS


June 11, 2012  Prince George

June 12, 2012  Williams Lake

June 14, 2012  Vernon

June 18, 2012  Port Alberni

June 19, 2012 Township of Langley


Time: 0800 to 1600
Registration Fee: $149.00 plus tax (includes lunch)

Register on-line by clicking on the FireWise Consulting Registrations link or register by mail, e-mail or fax by printing and filling out the form at the following link: Registration Form

GAO Report Results: OSHA and NIOSH Need to Work Together

Occupational health and safety should not solely be inspection, enforcement, and rulemaking. Regarding combustible dust workplace fire and explosion hazards, outreach, education, training, and research is essential. All these elements are included in the OSH Act. The enlightening GAO report sheds light on the fact that the OSH Act is not being adhered to. I encourage all EHS professionals to read the OSH Act, Sections 20, 21, 22 http://www.osha.gov/pls/oshaweb/owasrch.search_form?p_doc_type=oshact

Solely relying on a regulation in providing a warm and fuzzy feeling is not the complete solution. A prime example, would be the multitude of grain elevator explosions following the OSHA Grain Facility Standard http://www.osha.gov/dea/lookback/grainhandlingfinalreport.html
So now we have reached a point where X fatalities is not acceptable but Y fatalities is acceptable. OSHA does not have the resources to be everywhere at once. The time has now come in the 21st century where the paradigm must change to shared responsibility engaging all stakeholders.

In contrast,  "Clinical Professor of Environmental and Occupational Health Michael Silverstein claimed that OSHA and NIOSH have been working together for the past 40 years"
Then why  hasn't NIOSH been a primary stakeholder in the OSHA Combustible Dust rulemaking?
Full Committee Hearing - Time Takes Its Toll: Delays in OSHA’s Standard-Setting Process and the Impact on Worker Safety http://www.help.senate.gov/hearings/hearing/?id=a23b4eec-5056-9502-5d4a-c00679b2215c

Maybe this GAO report will open dialogue on establishing and coordinating local, state, and federal standardization, interoperability, compatibility, and responder health and safety to prepare for, train and respond to, mitigate, and recover from any incident by identifying requirements for an all-hazards incident response which includes OSHA, NIOSH, and US Fire Administration? http://www.cdc.gov/niosh/nas/ppt/QUADCharts11/ZBCS_FY11_QC.htm

The InterAgency Board (IAB) is a voluntary collaborative panel of emergency preparedness and response practitioners from a wide array of professional disciplines that represent all levels of government and the voluntary sector. The IAB provides a structured forum for the exchange of ideas among operational, technical, and support organizations to improve national preparedness and promote interoperability and compatibility among local, state, and federal response communities.https://iab.gov/mvv.aspx

Doesn't catastrophic ComDust related fires and explosions in the workplace warrant federal standardization, interoperability, and compatibility?

GAO Report: WORKPLACE SAFETY AND HEALTH, Multiple Challenges Lengthen OSHA’s Standard Setting http://www.help.senate.gov/imo/media/doc/Moran.pdf

"Improve coordination with other agencies: Experts and agency officials noted that OSHA has not fully leveraged available expertise at other federal agencies, especially NIOSH, in developing and issuing its standards. OSHA officials said the agency considers NIOSH’s input on an ad hoc basis but OSHA staff do not routinely work closely with NIOSH staff to analyze risks of occupational hazards. "

"However, OSHA can coordinate more routinely with NIOSH on risk assessments and other analyses required to support the need for standards, saving OSHA time and expense. In our report being released today, we recommend that OSHA and NIOSH more consistently collaborate on researching occupational hazards so that OSHA can more effectively leverage NIOSH expertise in its standard-setting process. Both agencies agreed with this recommendation."

This is only the tip of the iceberg of agencies not working together regarding workplace ComDust fire and explosion hazards. For example, OSHA has ignored the US Fire Administration in the ComDust Rulemaking process. When a ComDust related fire goes beyond the incipient stage, who you going to call to extinguish the fire?

Mountain Pine Beetle Infested Trees Moisture Content in Evaluating Fire & Explosion Hazards

Numerous MPB working papers were written for the Mountain Pine Beetle Initiative (MPBI) administered by the Canadian Forest Service. The MPBI began in 2002 and was a six-year package of programs with a total budget of $40 million.

Stakeholders will find a wealth of information in the numerous working papers such as moisture content in infested trees regarding time since death (tsd). The stages infested trees go through after the green stage include the red stage, where the tree shows characteristics of dying (i.e., red needles) in the stand for 2-4 years,and the grey-stage, where the tree has been dead in the stand for 5 or more years.

During the evaluation of moisture content (MC) it is important to understand that fiber saturation point (FSP) varies with tree species. FSP is when there is no longer any free water between the cell structures.(see page 18 .pdf)  NFPA 664 defines deflagrable wood dust when the moisture content (wet basis) is less than 25% and the median particle size is less than 500 microns.  Converting from dry-basis to wet-basis moisture content calculations.

A problem arises when the science is not applied when conducting a hazard evaluation of the fire and explosion properties of wood dust. When the raw material input changes from green wood with high moisture content to low moisture content MPB infested trees a management of change (MOC) is warranted.

For group members desiring additional info on MC here is a link to the OSHA ComDust NEP. Scroll down to Appendix E ,Combustible Dust Tests Conducted at SLTC

"Moisture in dust particles raises the ignition temperature of the dust because of the heat absorbed during heating and vaporization of the moisture. The moisture in the air surrounding a dust particle has no significant effect on the course of a deflagration once ignition has occurred.

There is however, a direct relationship between moisture content and minimum energy required for ignition, minimum explosive concentration, maximum pressure, and maximum rate of pressure rise. For example, the ignition temperature of cornstarch may increase as much as 122 Fahrenheit, with an increase of moisture content from 1.6 percent to 12.5 percent.

As a practical matter, however, moisture content cannot be considered an effective explosion preventive, since most ignition sources provide more than enough heat to vaporize the moisture and to ignite the dust. In order for moisture to prevent ignition of dust by common sources, the dust would have to be so damp that a cloud could not be formed." (Source: Fire Protection Handbook, 19th Edition). 

An excellent resource concerning moisture content in MPB infested trees versus non-infested trees is the paper Moisture changes in lodgepole pine before and after attack by the mountain pine beetle by Dr Rob Reid who worked at the Forest Entomology and Pathology Branch, Department of Forestry, Calgary, Alberta. Dr. Reid conducted moisture content studies on MTB trees near Invermere, British Columbia, and Banff, Alberta, in the period 1955-1960.

The nine page .pdf has excellent figures and tables illustrating moisture content in MPB infested trees versus non-infested trees. Many of the scientific papers written were the result of the $40 million dollar Canadian Mountain Pine Beetle Initiative (MPBI) program (2002-2008) which reference Dr Reid's 1961 paper.

The problem we have now is that industry has not utilized the wealth of scientific data acquired in the Mountain Pine Beetle Initiative (MPBI) in assessing fire and explosion risk when these infested trees are processed.

Resources
NFPA 664: Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities  
Moisture content of lumber produced from dead western white pine and Lodgepole Pine trees.

 Rate of deterioration, degrade and fall of trees killed by mountain pine beetle: A synthesis of the literature and experiential knowledge (2005)  
Current knowledge of characteristics and utilization of post-mountain pine beetle wood in solid wood products

A wood and fibre quality-deterioration model for mountain pine beetle-killed trees by biogeoclimatic subzone 
The mountain pine beetle : a synthesis of biology, management, and impacts on lodgepole pine (2006)

Understanding the WorkSafeBC Lakeland Mills inspection reports

Recently there has been extensive media coverage on the recently released WorkSafeBC Lakeland Mills inspection reports. Media accounts mention dust levels in the reports but fail to inform the public that the issue of dust was primarily respiratory health hazards of dust and not fire and explosion hazards of dust. There is a big difference. In many instances airborne levels of combustible dust can be indicative of engineering control measures such as local exhaust ventilation is not adequate or insufficient housekeeping.

Excerpts from Lakeland Mill Report

 

This inspection report focused on the MSI, Noise and Wood dust components of the provincial high risk strategy.

2/3/2009 page 33 Most processing saws and chipping heads are equipped with local exhaust ventilation, which appear to reduce accumulations of fine dust. No recent monitoring of exposure to wood dust has been conducted. Wood dust exposure will be further evaluated during subsequent inspections.  This is an item that should be re-evaluated due to the changes in productivity that has occurred over recent years and the fact the majority of the wood being processed is dry beetle killed pine

 

SRO/OHO Barry Nakahara and I inspected this worksite as part of the high risk provincial strategy

5/27/2010 page 67 We confirmed that hearing tests are being done regularly. We discussed potential dust exposure and the need for appropriate respiratory protection for workers performing clean up of dusty areas. The employer has recently conducted air monitoring for dust and exposures relating to the end-spraying operation. These results were reviewed and no significant problems were noted.

 

OSO Darren Beattie and I conducted an inspection of this jobsite on February 6, 2012 to assess compliance with the Workers' Compensation Act and the Occupational Health & Safety Regulation. A separate inspection report will be issued by OSO Beattie summarizing his observations.

2/9/2012 Page 112 We discussed the wood dust observed throughout the mill. At the time of inspection, the airborne concentration appears to be below the exposure limit (Non-allergenic wood dust EL = 2.5 mg/m3) in the work areas visited.  There are accumulations of piles of wood dust in various areas of the mill. We reviewed the requirement to prevent the accumulation of hazardous amounts of wood dust.

Resource
Lakeland Mills inspection reports

Guidance WorkSafeBC Directive Order to Sawmill Employers

Now that the topic of workplace combustible fire and explosion hazards is out the open in British Columbia  sawmills it is important for facility owners and managers to understand the steps in a risk assessment in developing engineering and administrative control measures. The missing link that has not been communicated to stakeholders is the importance of understanding the BC Fire Code which references NFPA 664 Standard for the Prevention of Fires and. Explosions in Wood Processing and Woodworking. Facilities. An excellent resource in understanding NFPA 664 is the 24 page .pdf document developed by the  Wood Machinery Manufactures of America (WMMA).


The BC Fire Code references NFPA 664 Standard for the Prevention of Fires and. Explosions in Wood Processing and Woodworking. Facilities. For example,  BC Fire Code (1998), Hazardous Processes & Operations (page 113 .pdf) Section Part 5.3. – Dust Producing Processes (page 115 .pdf)

Many don't realize that it is not WorkSafeBC which enforces the BC Fire Code but instead the Fire Commissioner ("Office") and the Office's jurisdiction over fire safety and fire protection in British Columbia. The Office is the senior authority having jurisdiction over fire safety and prevention in B.C. The Office administers the Fire Services Act and it regulations, and appoints and trains local assistants to the Fire Commissioner.

"where WorkSafeBC prevention officers observe what they believe to be a violation of the Fire Services Act or its regulations, prevention officers will notify the local assistant to the Fire Commissioner."

Solely relying on the WorkSafeBC regulation on combustible dust is not sufficient in undertaking a comprehensive risk assessment in addition to developing a combustible dust control program. An understanding of NFPA 664 as referenced in the BC Fire Code will assist immensely in conducting a safety review for combustible dust in sawmills.

To assist stakeholders WorkSafeBC published OHS Guideline G5.81 Combustible Dust-Sawmill Facilities (April 25, 2012) The recent guideline provides information on a Combustible Dust Program which includes elements of hazard mitigation; facility risk assessment, written combustible dust control program, and a hazardous communication program.

Update April 28, 2012 WorksafeBC Bulletin — Clean-up of hazardous combustible dust
"WorkSafeBC has prepared a simple one-page bulletin in safe cleaning procedures of combustible dust that  protect workers."

Resources 
WorkSafeBC Directive Order to Sawmill Employers 
NFPA 664 Combustible Dusts – Overview (WMMA)
BC Fire Code (1998)
OHS Guideline Combustible Dust Sawmills

Relying on housekeeping as a first line of defense against explosion and fire is a false economy

Why going cheap on the dust collection & control system is short sighted...

We all know that our cars and trucks have air and oil filters to catch dust to avoid abrasive wear of the engine. We have seen news articles about how airborne dust is not good for jet engines - like when that Icelandic volcano erupted in 2010, or the Argentinean eruption in 2011.

So, why do so many industrial operations let their dust collection systems get plugged up and fail to perform? Assuming that they bother to install adequate dust controls in the first place?

One common complaint from the people who run foundries and factories is cost - buying a dust control system costs some serious coin, and too many operations try to go bottom dollar when they buy equipment. 

Another issue is maintaining and cleaning the equipment - this requires technicians with some training, whereas handing a laborer a shovel or a broom is a good way to keep him busy when things are a bit slow for making product.

This is especially problematic when the dust in question is combustible.

I've lost track of the mills and factories I've consulted for who have had "snowdrifts" of dust piled up because they didn't have the right dust collection and control system, and instead relying on housekeeping to deal with the mess.

 Fortunately, most of these operations were making steel or cement, and slag and rock dust don't burn or explode. They are abrasive however, and the dusts stick to exposed lubricated parts, like the cables of the hoist of an overhead crane, or the packing of a pillow-block bearing.

 It's difficult to quantify how much service life get eaten up by the grit grinding away on the machinery, but a knowledgeable maintenance superintendent can do predictive maintenance for his/her own shop, and develop the trend data.

Things get more complicated when the dust has hazardous qualities, such as toxicity or flammability.

OSHA has a distinct preference for engineering controls of such dusts - it makes sense to control and confine the potential hazard, making the work environment safer.

When we look at some key fatal accidents, we find that the dust control systems were no longer working as designed or installed.

The Hayes Lemmerz explosion in Huntington, IN in 2003 was largely due to the inadequacy of their dust collection system  which was leaking aluminum powder from its ductwork.

 The rash of explosions and fires at Hoeganaes in Gallatin, TN in 2011 were exacerbated by the prevalence of combustible iron powder due to the lack of adequate function of the ageing dust control equipment.

   The Imperial Sugar explosion in Port Wentworth, GA in 2008 was also largely due to inadequate dust controls. 

When we look at the accident investigation photographs from these incidents, the prevalence of fugitive dust (dust which has escaped containment) is obvious - and frightening to a knowledgeable observer.

Housekeeping presents several problems as a means to control combustible dust. A major problem is that dust will deposit on any horizontal surface - like roof beams, conduits, and the top surfaces of machinery and internal enclosures (electrical & machinery rooms for example).

Then there is the issue of just how one goes about cleaning up the accumulated fugitive dusts. The CSB report on the explosion and fire at CTA Acoustics in Corbin, KY in February of 2003 shows that sweeping and blowing combustible dust can easily generate a combustible cloud, which can react with any ignition source.

Conventional industrial vacuum cleaners ("Shop Vacs") are not much better, since they lack specific grounding and venting to prevent internal explosion of the dust which they are sweeping up.

The recent sawmill explosions in British Columbia in January and February would appear to also be due to fugitive dust (final reports from the BC government are not yet available). The news reports indicate that the mills were operating with reduced staff, which would indicate that there were fewer employees available for maintenance and housekeeping.

Factor in a drier source of timber - beetle killed trees - and the possibilities for dust problems become all too real.

The destructive fire at the Swany White flour mill in Minnesota in December of 2011 appears to be another example of fugitive dust catching fire - possibly due to a hot bearing on the ~100 year old milling and sifting equipment.

So, relying on housekeeping as a first line of defense against explosion and fire is a false economy - not only is there a greater risk to the workers workers, but the maintenance costs for machinery are higher, due to increased abrasion from dust getting into the moving parts of machinery.

Contributed by Eric Anderson
Vice President
Renewable Energy Technologies, Inc.
eanderson@eandersonventilation.com

Decade anniversary: Silo fire at Tire Recycling plant

NCNewsPress.com Article Feb 6, 2012
U.S. Fire Administration/Technical Report Series: Tire Recycling Facility Fire Nebraska City, Nebraska USFA-TR-145/January-February 2002

Excerpts from US Fire Administration report:

The Facility
The plant had been inspected by Nebraska State Fire Marshal’s Office on more than one occasion and had a history of poor housekeeping as well as a track record of poor equipment maintenance. There had previously been two fires at the site, as well as two fires at another EnTire facility, also located in Nebraska City.

The Incident
The explosion expelled chunks of rubber that were approximately two to four inches in diameter. Debris was hurled 300 to 400 feet away, damaging and destroying apparatus and equipment as well as injuring the thirteen firefighters

Investigation
The State Fire Marshal has determined that the probable cause was a faulty bearing in the stiff leg auger which carried the crumb rubber from the ground level to the top of the silos.

The bearing overheated igniting the rubber debris around the sugar base. A contributing factor was the poor housekeeping practices. No definite cause of the explosion has been identified,

Lessons Learned
Most local zoning and building codes do not adequately address facilities of this type. Traditionally, volunteer fire departments do not become involved in local zoning issues and often lack the resources to properly preplan target hazards.

The facility in this incident was not designed for its use, nor were there adequate safe guards built into the process since the com­plex already existed and was modified to accommodate this particular process.

Fire departments should become more proactive in the permitting and zoning process and should endeavor to ensure appropriate code enforcements in facilities of this type, whenever it is possible to do so.

How Fast Will the Fire Spread in Your Dust Layers Compared to Gunpowder (BZ 6)

A recent news account of a paper dust fire rapidly spreading a distance of 300 feet, brings to mind the importance of understanding the burning behavior of combustible dust layers.

It is time all stakeholders understand the burning behavior of their combustible dust through VDI 2263 lab test. Under elevated temperatures a layer of dust can escalate from a potentially non-spreading fire to a spreading fire. Example of BZ #'s : Salt (BZ 1) Gunpowder (BZ 6) Below are several files from BIA Report 13-97 "Combustion and explosion characteristics of dust":
(BZ 1-3 No Fire Spread)
(BZ 4-6 Fire Spread)

Index File

Information and Description File page 21/Combustion Test
Organic Products

Chemical Products

Inorganic Products

Miscellaneous Products

In the last file, group1_2.pdf , go to second page of material data in the last column on the right under combustibility test to find the BZ number (1-6) Note: The BZ numbers should only be used as a guideline since the dust at your facility will have unique and different characteristics of particle size, shape, moisture content, chemical composition, etc.

Another resource in locating BZ numbers is the Gestis-EX Dust database. Not all the dust samples in the database will have the BZ number. So you will have to search for several different samples in finding a BZ number to use as a guideline.

Revise Combustible Dust National Emphasis Program (NEP): Poll

Combustible dust related fires and explosions are occurring throughout the manufacturing and non-manufacturing sectors that are not specifically recognized in Appendix D-1 & D-2 of the OSHA Combustible Dust National Emphasis Program (NEP). 
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=directives&p_id=3830

Recently a CSB recommendation in the Hoeganaes Case Study instructed OSHA to revise the Combustible Dust National Emphasis Program (NEP) to add industry codes for facilities that generate metal dusts (e.g., North American Industrial Classification System, NAICS, code 331111 Iron and Steel Mills, and other applicable codes not currently listed)..

What about the dozens of other NAICS having a history of combustible dust related fires and explosions that are not recognized in the ComDust NEP?